NEW ORLEANS — Dr. Lauren Morris's dental office is in sight of one of the pumping stations designed to push water out of New Orleans. But despite that proximity, the roughly year-old business has already flooded. Now with a storm in the Gulf threatening heavy rain and the June 1 start to hurricane season nearing, she's worried.

"It brings on a lot of stress," the dentist said. "Will we have to shut down the business for a couple of days, weeks, because we might get water?"

Morris was one of many city residents last Aug. 5 left worrying over their city's aging drainage system when a powerful storm unexpectedly dropped more than 9 inches (22 centimeters) of rain in some areas. In some neighborhoods, businesses flooded. Residents watched as their cars were submerged. People kayaked through the streets. The problems were compounded when officials first said the drainage system was working only to later have critical problems surface in a city still scarred by Hurricane Katrina's flooding in 2005.

The low-lying city has a particular challenge when it comes to drainage. Rainwater is pumped out through a century-old system of canals, drainage pipes and pumps — all suffering from decades of neglect laid bare during last summer's flooding.

A months-long investigation is currently under way to determine what went wrong. In the meantime, an interim team at the city's Sewerage and Water Board — one of the key agencies responsible for drainage — is getting ready for hurricane season, and they point to some improvement.

"If you look at where we were back in August and where we are today, we're definitely better off," said interim operations manager Joe Sensebe. More pumps are operating, and the system has 2½ times more power-generating capacity than it had back in August, he said. The agency also has a system that allows operators to see in real-time how the pumps and turbines are operating instead of relying on radio, said the agency's communications director Richard Rainey.

But Sensebe and others have cautioned that the system can't prevent all flooding. An intense rainstorm or a slow-moving hurricane that sits over the city could overpower it.

New Mayor LaToya Cantrell was barely on the job when a storm last Friday dropped as much as 2.5 inches (6 centimeters) of rain an hour in some areas. Many residents watched the rapidly-rising water and wondered if it was a repeat of Aug. 5.

"This past Friday's rain event was a tough one," Mayor Cantrell said during a news conference. "We can do better, and we will but I do not want to give a false narrative to our people."

The pumps and their ability to drain the system are part of the problem, said Cantrell. But the city also needs to be looking more toward things like ripping up concrete, building water retention ponds and underground cisterns. All of these so-called green infrastructure projects are designed to let rainwater seep slowly back into the earth instead of pumping it out. She also faulted the previous administration, saying many improvement projects had been stuck in a bottleneck.

Councilmember Jason Williams said a key difference between last Friday's rain and the August flooding was that last year the water sat for hours even after the rain stopped — anecdotal evidence the pumps were not working. On Friday, it receded quickly, making him hopeful the drainage system is better. But he says there's still a huge amount of work to be done to a system that has suffered decades of neglect.

For example, in August he toured parts of the drainage system and found some areas so clogged with soil that trees were growing.

"Typically in a city you might have one main issue," he said. But in New Orleans the problems range from pumps to drainage canals to faulty administration and more. "It's a beast of a problem."

During last Friday's storm, Dwayne Boudreaux's Circle Food Store took on some water. Not as much as last August, when water was knee-deep in parts of his grocery store in the historic Treme neighborhood, but enough to leave him questioning whether anything's really improved. Now with hurricane season approaching, he's worried.

"It wasn't a hurricane that hit me on Aug. 5. It was just a hard rain. It wasn't a hurricane Friday. It was just a hard rain. I don't know what a hurricane would do," he said.